Chapter 1: Introduction to genetics

A brief introduction about myself  Southwest Teachers’ University, Bachelor  Sichuan University, Master, Ph D  now: Hubei University  Swedish University of Agricultural Sciences

Why do I want to teach in English?  China is becoming more and more international  All the best scientific journals are in English  We have to be able to communicate in English  What is the problem with our learning English

What should we achieve?  Communicate in English  Read English literatures  Know the basics of genetics  Know how to work with science

Science and Civilisation in China

The question of Joseph Needham  Why did modern science originate in western countries instead of China?  Why can’t we native Chinese scientists get Nobel prize?  Why could Mendel discover the two basic genetic laws?  What should we learn from Mendel, Morgan, Watson, Crick, Etc.?

How will we go ahead?  I: teach a few chapters  You: teach the other chapters  We: discuss

1.1 What is genetics?  genetics :The branch of biology that deals with heredity variation.  heredity : the similarity between progenitors and progeny  Variation: difference between generations and individuals of the same species

1.2 History of genetics  Prehistoric times: domesticated animals and cultivated plants Our ancient ancestors learned that desirable and undesirable traits are passed to successive generations and that by influencing their breeding, many desirable varieties of animals and plants could be obtained.

The Greek influence: Hipocrates Hipocrates argued that male semen is formed in numerous parts of the body and is transported through blood vessels to the testicles. Pangenesis: Particles or fluids from various parts of the body accumulate in germ cells, and are transmitted to the offspring. This theory believed in the passing on of characters acquired during lifetime of the individual.

Hipocrates

The Greek influence: Aristotle  Aristotle proposed that male semen was formed from blood rather than from each organ, and that its generative power reside in a vital heat that it contained.

Aristotle

Before Mendel: Preformation  Leeuwenhoek and his students believed they saw through their microscope small encapsulated creatures within the sperms.  Bonnet ( ): An embryo contained a smaller embryo, which contain another smaller embryo, so on.

Before Mendel: epigenesis  Wolff suggested that organisms develop by epigenesis, i.e., development starts from undifferentiated fertilized egg and proceeds through successive formation and addition of new parts which did not exist there before.

Doctrine of use and disuse  Lamark ( ) proposed that organisms acquire or lose characteristics that then became inheritable.

 Lamark

Pangenesis and the inheritance of acquired characteristics  Charles Darwin described the physical units representing each body part that were gathered by the blood into the semen. He felt these units determined the nature or form of each body part and they could respond in an adaptive way to the external environment. Once altered, such changes would be passed onto offspring, allowing for the inheritance of acquired characteristics.

Charles Darwin

August Weismann and Francis Galton  Weismann cut off the the tails of mice for 22 generations, yet the newborn displayed tails just as long as those of their ancestors.  Galton performed blood transfusions among different breeds of rabbits, without any hereditary consequences.

August Weismann

Francis Galton

Gregor Mendel

 Mendel published his classic paper in In this paper Mendel demonstrated a number of statistical patterns underlying inheritance and developed a theory involving hereditary factors in the germ cells to explain these patterns.

After Mendel  1900, De Vries ， Correns and Tschermak rediscovered Mendel’s paper  1903, Sutton and Boveri, Chromosomal theory of inheritance  1909, Johansen coined gene for genetic factor  Around 1910, Morgan and his students Sturtevant ， Bridges and Muller: gene theory

Morgan TH

After Mendel  1927, Muller and Stadler: irradiation genetics  1940, McClintock: transposon  1941, Beadle and Tatum: one gene for one enzyme  Avery (1944), Hershey (1952): genetic material is DNA instead of protein  1953, Waston and Crick: double helix model

Barbara McClintock  Discovered transposon in 1940 and was awarded Nobel Prize in 1983.

Watson and Crick

After Mendel  1973, genetic engineering.  1990, Human Genome Project→genomics.  1997, Clone of Dolly.  Functional genomics; Protemics

Genetics and Agriculture  Hybrid vigor  Disease resistance  Pest resistance  Herbicide resistance  Select for various mutants  Utilization of bacteria to produce useful industrial materials

Yuan Longping  The father of hybrid rice

Fu Tingdong  Found the first useful male sterile line-- CMS Polima in Rapeseed.

Genetics and Medicine  Understanding the genetic basis of many disease including cancer.  Development of new medicines through genetic engineering.

Genetics and environment protection  Utilization of genetically modified plants to clean heavy metals.  Utilization of genetically modified bacteria to clean the water.  etc.